and Telephony 


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S.S. Mauretania at Full Speed. 790 Ft Long, 3200 Tons Gross Weight, Trial Speed 

25^ Knots per Hour. Frontispiece. 







WIRELESS TELEGRAPHY 

AND 

TELEPHONY 

POPULARLY EXPLAINED 


BY 

WALTER W. MASS IE 

AND 

CHARLES R. UNDERHILL 


WITH SPECIAL ARTICLE BY NIKOLA TESLA 



NEW YORK 

D. VAN NOSTRAND COMPANY 
23 Murray and 27 Warren Streets 
1908 






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Copyright, 1908, 

BY 

D. VAN NOSTRAND COMPANY 


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ROBERT DRUMMOND COMPANY PRINTERS. NEW YORK 








PREFACE 


Wireless Telegraphy is mentioned in almost every 
publication of to-day, and enters into conversation be¬ 
tween all; yet how few really know what it means. 

There have been several books written on the subject 
for the expert or technical man, but so far nothing has 
been written that explains it in a way that every one may 
understand. 

In this book the authors use simple expressions, con¬ 
taining no technical words, so that all may obtain a clear 
idea of the inception and development of this much-talked- 
of art. 

We here describe the substance through which signals 
are sent, the theory of the propagation of waves, method 
of generating and receiving the waves, the apparatus 
used, and, finally, the uses, limitations, and possibilities 
of wireless telegraphy both commercially and financially. 

. Providence, R. I. WALTER W. MASSIE. 

New York. CHARLES R. UNDERHILL. 

July 15, 1908. 

iii 




CONTENTS 


CHAPTER I 

The Secret of Wireless Telegraphy 

PAGE 

1. Nature’s Wonderful Medium. x 

2. Vibrations in the Ether. 3 

CHAPTER II 

Principle and Theory of Wireless Telegraphy 

3. Principle. 6 

4. Synchronous Wave Motion and Tuning. 8 

5. Theory. 11 

CHAPTER III 
The Apparatus Used 

6. General Outline. . 14 

7. The Induction Coil. 14 

8. Leyden-jar Battery..'. 15 

9. The Spark-gap. 18 

10. Production of Oscillatory Discharge. 19 

11. The Inductance. 20 

12. The Antenna. 22 


v 















VI 


Contents 


PAGE 

13. Tuning the Transmitting Apparatus. 22 

14. The Receiving Apparatus. 26 

15. Detectors. 27 

CHAPTER IV 
Method of Operating 

16. Switching Device. 34 

17. Sending the Message. 34 

CHAPTER V 
Historical 

18. Early Attempts. 39 

19. Development of Wireless. 40 

CHAPTER VI 

The Uses of Wireless Telegraphy 

20. Public Service. 44 

21. Value to Shipowners. 45 

22. Telegraphing over Land. 47 

CHAPTER VII 

Possibilities and Abuses of Wireless Telegraphy 

23. Commercial Conditions. - x 

24. The Present State of the Art. 52 

25. Interference and Government Regulation. 

26. The Outlook and Prophecy. 61 

Wireless Telephony.:. 63 


The Future of the Wireless Art (by Nikola Tesla). ... 67 

















WIRELESS TELEGRAPHY 


CHAPTER I 

THE SECRET OF WIRELESS TELEGRAPHY 

i. nature’s wonderful medium 

The term wireless telegraphy is commonly used in con¬ 
tradistinction to the electric telegraph in which it is 
necessary to employ a wire as an artificial conducting 
medium between stations. 

Nature provides a medium, called the ether* through 
which intelligence may be communicated over sea or 
land; and by means of which otherwise impossible re¬ 
sults are accomplished. The ether exists between the 
planets and the stars, and all the other heavenly bodies, 
and has no conceivable end; hence when we speak of the 
ether, we tacitly refer to the universe. 

This infinite sea of ether is continually in a state of 
intense turmoil, performing its mission of transferring 


* This term ether has absolutely no connection with the drug of the same 


name. 





2 


IVireless Telegraphy 


energy, radiated from the sun, to our earth and the other 
planets, as well as other influences due to myriads of 
heavenly bodies outside of our own solar system. 

Transmission of energy through the ether takes place 
in the form of wave motion, and these waves are known 
as electromagnetic waves. Since light is one form of wave 
motion, we may make use of it in illustrating the presence 
of ether, by describing the following well-known experi¬ 
ment. 

An ordinary electric bell and small battery are placed 
in what is known as a receiver, the cover being a glass 
dome, and an air-pump is then started which will event¬ 
ually pump out all the air from the receiver in which 
the electric bell is ringing. Although the cover, or glass 
dome, is over the bell, it can be plainly heard, and the 
clapper can be seen vibrating rapidly. As the air is 
pumped out, however, the sound of the bell becomes 
fainter and fainter, until, finally, it is no longer heard, 
although the bell can still be seen as plainly as before, 
and the clapper vibrating as rapidly as ever. Therefore 
it.is very evident that something remains in the receiver 
after the air has been removed; for, while we cannot hear 
the bell, we can see it, and we could not see it if there 
were not some medium to convey the reflected light waves 
from the bell to the eye. 

While the earth’s atmosphere extends but a compara¬ 
tively small distance, the extent of the ether is infinite. 

The universe is a sea of absolute darkness, and if it 


The Secret of Wireless Telegraphy 3 

were possible for us to place ourselves, say, midway be¬ 
tween the moon and the earth (in which position we would 
be over one hundred thousand miles from any air), we 
would see all the heavenly bodies, and even our own forms, 
as the light waves would be intercepted and reflected 
by them; but, otherwise, all would appear as an intense 
starlit night, with the unusual features of having the 
sun visible in greatly increased brilliancy, as well as the 
moon appearing four times its usual size, and the novelty 
of seeing our own earth rivalling the moon in size and 
splendor, even under these conditions, more than ten¬ 
fold. 

Every manifestation of power on the earth at some 
time came through the ether in the form of waves, and 
even when we enjoy the cheerful sunshine we are, in 
reality, experiencing the result of the absorption of the 
ether waves from the sun by our own persons. 


2. VIBRATIONS IN THE ETHER 

Light, heat, and wireless waves are electromagnetic 
waves (and, therefore, wave motions of the ether), the 
only difference being in their relative rates of vibration; 
their velocity, in free ether, being the same, viz., 186,000 
miles per second. They do not, however, traverse all 
substances with like velocities. 

The sun is constantly disturbing the sea of ether, not 
by a single train of waves, but by wave trains of vary- 


4 


Wireless Telegraphy 


ing frequencies, and the higher rates of vibration are 
so intense that the mind can scarcely conceive them. 
When we think of 767 trillions of vibrations per second, 
it has little definite meaning to the lay mind; yet science 
has devised means to accurately determine so high a rate, 
which represents the extreme violet of the spectrum, and 
is the highest rate of vibration which our eyes are capa¬ 
ble of detecting. The lowest rate of vibration to which 
our eyes are sensitive is 392 trillions per second, which 
represents the extreme red of the spectrum. 

Our eyes are sensitive to all the other rates of vibra¬ 
tion between the extreme violet and the extreme red 
and all these complex waves, acting together, produce 
what we call daylight. The waves which produce a sen¬ 
sation of light when they fall upon the eye are, naturally, 
called light waves, although the photographic plate is 
affected by light waves which are outside the rates of 
vibration to which the eye is susceptible. 

When the ether waves impinge upon a body of ordi¬ 
nary opaque mass, it may be warmed, the energy being 
transformed into heat. While the light waves may pro¬ 
duce heat, there are also ether waves called dark heat 
waves, which come at a rate of vibration much too slow 
to produce a sensation of light. 

We say that glass is transparent because it does not 
appreciably obstruct the ether waves. We may sit near 
a closed window and enjoy the warmth of the sun because 
the glass, being transparent, does not arrest the ether 


The Secret of Wireless Telegraphy 


5 


waves, and, therefore, the glass is not warmed; but our 
own bodies, being opaque, do absorb them, thus pro¬ 
ducing heat, which our sense of feeling makes manifest 
to us. 

The rate of vibration in the ether, as artificially pro¬ 
duced in wireless telegraphy, is extremely slow as com¬ 
pared with that of the light waves, ranging from approxi¬ 
mately 1,500,000 to 100,000 per second. The wave 
length, in any such case, is found by dividing the velocity 
by the rate of vibration; hence for the extreme violet 
of the spectrum, the wave length would be btitoo inch, 
and for the extreme red, ^ 3-^-0 inch, while those 
employed in wireless telegraphy vary from about 650 feet 
to nearly two miles. 

As is well known, the ether in proximity to the earth 
is in continual disturbance, which creates the magnetic 
field surrounding the earth. This manifests its presence 
in many ways; the most common is its influence on the 
magnetized needle of a compass, which causes it to point 
north and south. Wireless waves are propagated through 
this magnetic field, and follow the curvature of the earth. 

When we contemplate the wonders of nature, and grad¬ 
ually fathom her mysteries, that which before seemed 
impossible now becomes an established fact, and even 
so wonderful an art as wireless telegraphy loses its magic 
when we study into the laws which govern it, and see it 
take its place, with marvels of the past, in the service 
of man. 


CHAPTER II 


PRINCIPLE AND THEORY OF WIRELESS 

TELEGRAPHY 

3 . PRINCIPLE 

The art of wireless telegraphy is based upon wave 
motion, and an analogy is found in the wave motion of 
water, as the following explanation should make clear. 
Picture a small pond of still water, with a chip or twig 
floating upon its surface, in full view of the observer. 
Now if a stone be thrown into the water, the sudden 
impact of the stone would cause ripples, or small waves, 
to radiate from the point of impact of the stone with 
the surface of the water, the waves becoming weaker as 
the circles become larger, i.e., as the distance from the 
point of impact becomes greater. As the waves arrive 
at the point where the chip is floating, they will impart 
motion to the chip; hence the observer will be aware 
that there has been some disturbance in the water. (See 
Fig. 1.) After the waves have ceased, the chip will again 
lie motionless upon the surface of the water. 

It is obvious that the distance over which the signals 


Principle and Theory of Wireless Telegraphy 7 

may be sent by this means will depend (a) upon the force 
employed to start the waves, and (b) upon the lightness 
of the chip, or its sensitiveness to the motion of the waves. 
Moreover, if there were grass or other obstructions in the 
pond between the point where the waves are started 
and the point where the chip is located, some of the energy 
would be absorbed in swaying the grasses; hence the 
effect upon the chip would not be so great, and the sig¬ 
nalling distance would be lessened. Or if there were an 



Fig. i.—Wave Motion in Water. 

obstruction in the path of the waves, as, for instance, a 
protruding rock, the waves would be distorted by this 
obstruction; hence less energy would reach the chip. 

It is also obvious that any number of chips might be 
placed at any number of points within the affected radius 
of wave motion, and all would be moved by the waves. 

When it is considered that these water waves cover 
an ever-increasing area as the circles expand, and that 
the actual energy which disturbs the chip is an extremely 
small part of the total energy in the entire circular wave, 
it should be clear why so great an amount of energy is 












8 


Wireless Telegraphy 


required at a wireless sending station in order to operate 
a very sensitive receiver many miles away. 

If we consider that the light chip resting upon the sur¬ 
face of the water has practically no inertia, it will respond 
to almost any wave length, and, therefore, if the water 
were disturbed from some other source than the stone 
referred to, and while signals were being sent by means 
of the stone, confusion would result, as the chip would 
respond to the waves from both sources, and, for this 
reason, no accurate signals could be made out by watch¬ 
ing the motions of the chip. However, this difficulty 
may be overcome by employing a transmitting device 
which will send out waves of a certain length, and a re¬ 
ceiving apparatus which shall respond only to the wave 
length of the transmitter. 

4. SYNCHRONOUS WAVE MOTION AND TUNING 

If a weight suspended by a spiral spring, or a rubber 
band, be given a blow so as to cause it to move up and 
down, the weight will oscillate uniformly; that is, a defi¬ 
nite number of times per minute, the frequency depend¬ 
ing upon the elasticity of the spring, or rubber band, and 
the weight of the suspended mass. 

Now assume this device placed over the pond of still 
water, as depicted at the left in Fig. 2, and set in motion 
as described above. On each downward movement of 
the weight it will touch and disturb the water, and, since 


Fig. 2.—Principle of Synchronous Wave Motion. 


Principle and Theory oj Wireless Telegraphy 


9 


























































































































io IVireless Telegraphy 

it oscillates uniformly, it will create, or generate, a defi¬ 
nite number of waves per minute, all being of uniform 
length and size. 

If now we substitute a similar spring and weight for 
the chip as a receiving device (shown at the right in Fig. 
2), and place this within the radius of the transmitted 
waves, these waves in passing will set it in motion, as it 
oscillates at exactly the same frequency as the transmit- 
1 ting weight. If the receiving device did not oscillate at 
the same rate as the transmitter, and, therefore, was not 
in harmony with the transmitted waves, these would tend 
to counteract any motion imparted to the receiving spring- 
suspended weight, as the following example should make 
clear. Assume the receiving weight to be of such dimen¬ 
sions that it will oscillate once per second. Now if the 
sending weight be generating waves at the rate of two 
per second, the first wave will give the receiving weight 
an upward motion at its own frequency; but just as it 
starts on its downward stroke, the second wave will strike 
it, thus preventing any further motion of the weight. 

It is, therefore, evident that the escillations of the re¬ 
ceiving device would be destroyed if the frequency did 
not harmonize with that of the sending device. Tuning 
is absolutely necessary for the successful operation of 
wireless telegraphy, and it should be thoroughly under¬ 
stood before continuing. 


Principle and Theory of Wireless Telegraphy 


ii 


5. THEORY 

Wireless signals are a wave motion in, or disturbance 
of, the magnetic forces of the earth, and are propagated 
through this magnetic field, following the curvature of 
the earth, just as a tidal wave would follow the surface 
of the ocean. Practice indicates that the nodel points 
of the waves are at, or near, the earth’s surface. 

As explained in Chapter I, ether waves do not traverse 
all substances with like velocities; this explains why 
wireless signals are propagated many times farther over 
water than over land, as the waves traverse air and water 
at practically the same velocities. In land the waves 
travel at a much slower rate. 

Now to produce, electrically, the results described by 
the analogy of water, we must employ means for creating 
waves in the earth’s magnetic field, and use an electrical 
spring and weight, so to speak. The electrical spring 
effect is obtained by the electrical phenomena of capacity. 
Any surface of metal possesses capacity, which is the power 
to retain a charge of electricity. When this is disturbed 
it has the same elastic principle as the spring. 

The inertia of the weight is represented, electrically, 
by the term inductance , which effect is produced when a 
constantly changing current is passed through a coil of 
wire. This causes the continually changing current to 
react upon itself, and, consequently, produces a retard¬ 
ing effect. 


12 


Wireless Telegraphy 


Referring to Fig. 3, let C represent a capacity connected 
to the ground MN through the adjustable inductance /. 
If means be employed to cause the residual charge of this 
capacity to oscillate, it will, in turn, cause a wave-like 
motion of the electromagnetic forces of the earth similar 
to the wave motion in water. 

If either the capacity or inductance is increased, the 
vibrations will be slower, and the wave length will be 



greater. The waves thus generated are propagated 
through the earth’s forces in ever-increasing circles, exactly 
as in the case of the water waves. 

C' in Fig. 3 represents the receiving capacity connected 

to the ground through the inductance in the same 

• 

manner as at the sending station. This capacity, of 
course, also contains a residual charge which is dormant 
under normal conditions, but as the wave front glides 
by the station, the rising and falling of the waves will 
impart a slight oscillatory motion to the residual charge. 








Principle and Theory of Wireless Telegraphy 13 

Means for manifesting these oscillations permit us 
to correctly read all signals sent out from the transmit¬ 
ting station. 

To clearly receive all signals transmitted from the send¬ 
ing station, it can be readily understood that the capacity 
and inductance must be adjusted to give exactly the 
same frequency; otherwise the natural frequency of 
the circuit would counteract the forced oscillations set 
up by the received waves, thus causing an interference 
or prevention of oscillations in this particular receiving 
station. Of course this would have no detrimental 
effect on other receiving stations which might be adjusted 
to harmonize with the waves. 


CHAPTER III 


THE APPARATUS USED 

6. GENERAL OUTLINE 

The production of electromagnetic waves requires a 
source of current, means for interrupting a unidirectional 
current (or an alternating current may be used), means 
for changing the interrupted or alternating current into 
low-frequency high-pressure currents, means for trans¬ 
forming these into high-frequency high-pressure oscilla¬ 
tions, and means for utilizing these oscillations to form 
the electromagnetic waves. 

At the receiving station means must be provided for 
intercepting the waves, and retransforming them into 
electrical oscillations; means for detecting the enfeebled 
oscillations, and for manifesting and translating them 
into readable signals. 

7. THE INDUCTION COIL 

The function of the induction coil is to change, say, a 

battery current of low pressure and comparatively large 

flow, to a current of great pressure and small flow; or, 

14 




The Apparatus Used 


i5 


in other words, it transforms, or changes the character 
of, electrical energy. 

An induction coil is shown in Fig. 7, at the left. 
This is also known as a Ruhmkorff coil in honor of its 
inventor. By its use electrical energy at pressures which 
might scarcely be felt even when placed across the tongue 
may be transformed into pressures so great as to render 
a person unconscious, or to even cause death. 

Another form of induction coil is called a transformer . 
The Ruhmkorff coil is operated by means of an inter¬ 
rupted unidirectional current, while the transformer is 
operated by an alternating current, i.e., a current which 
flows rapidly and alternately in opposite directions. 
Both of these devices are operated by, and conse¬ 
quently deliver, currents of very low frequency, as com¬ 
pared with the frequency required to generate the wire¬ 
less waves. 


8. LEYDEN-JAR BATTERY 

A frequency of at least 100,000 vibrations per second 
is required to form the wireless waves, and since it is 
impossible to practically obtain this frequency by mechan¬ 
ical means, the Leyden jar is employed for this purpose. 
This device consists of two pieces of tin-foil separated 
and insulated from each other by glass, or other suitable 
material. 

A group of these jars, when connected together, con- 


Wireless Telegraphy 


16 


stitutes a battery of Leyden jars , which has the same 
effect as a much larger single jar. Instead of being in 
the form of a round jar, this device is sometimes made 
in a flat form; that is, the glass and, consequently, the 
sheets of foil are flat. 

When the terminals of a Leyden jar are connected to 
a source of electrical energy, it will receive and retain a 



Fig. 4.—Types of Leyden Jars. 


charge equal in electrical pressure to that of the source 
of energy. If, after receiving a charge, its terminals be 
brought near one another, a sudden discharge takes 
place in the form of an electric spark which, while ap¬ 
pearing to be single and momentary, has been found by 
experiment to consist of a series of alternating flashes 
in rapid succession, each flash lasting less than one hun¬ 
dred thousandth part of a second. The frequency of 
these oscillations is regulated by the capacity, or size, 





The Apparatus Used 17 

of the Leyden jar; the smaller the capacity, the greater 
the frequency. 

The oscillatory discharge of the Leyden jar was first 
noticed by Prof. Joseph Henry in 1842. Von Helmholtz 
in 1847 said: “We assume that the discharge of a Leyden 
jar is not a simple motion of the electricity in one direc¬ 
tion, but a back-and-forward motion between the coat- 



Fig. 5.—Battery of Leyden Jars. 


ings in oscillation, which becomes continually smaller 
until the entire vis viva is destroyed by the sum of the 
resistances.” In 1853 Lord Kelvin proved the oscillatory 
discharge mathematically, and in 1859 Feddersen demon¬ 
strated it experimentally, by employing a rapidly revolv¬ 
ing mirror. 







18 


Wireless Telegraphy 


9. THE SPARK-GAP 

The device through which the oscillatory discharge 
of the Leyden jars takes place is known as the spark-gap. 
This consists of two metal rods insulated from one another, 
and with their ends about one inch apart, although this 



Fig. 6.—Spark-gap with Muffler, Surrounded by 

Inductance. 

distance may be varied at will by means of an adjusting 
device. 

As the high-frequency discharge across the spark-gap 
emits a loud, crashing sound, it is usually surrounded 





The Apparatus Used 


19 


by a “muffler” to deaden the noise. The muffler is shown 
in Fig. 6, and is provided with peep holes, in which glass 
or mica is set, in order that the operator may at all times 
be able to watch the condition of the “spark.” 

IO. PRODUCTION OF OSCILLATORY DISCHARGE 


In Fig. 7 is shown the induction coil, Leyden jars, and 
spark-gap properly connected to produce the oscillatory 



Fig. j '— Connections of Apparatus to Produce the 
Oscillatory Discharge. 


discharge. This takes place in the following manner. 
In Art. 7 we explained how, by means of the induction 









20 


Wireless Telegraphy 


coil or transformer, a current of low pressure is transformed 
into a current of high pressure, but of low frequency, 
and this high-pressure current is utilized to charge the 
Leyden jars. 

When the Leyden jars are fully charged (which action 
takes place almost instantaneously), the resistance of the 
spark-gap is “broken down,” and the oscillatory dis¬ 
charge takes place between the points of the spark-gap. 

II. THE INDUCTANCE 

In order to successfully utilize the high-frequency 
oscillations due to .the discharge of the Leyden jars across 
the spark-gap, a controlling device is necessary which 
shall vary the electrical inertia of the circuit into which 
these oscillations are to be delivered. 

Adjustment is obtained by varying the number of 
turns of wire in the oscillating circuit. In Fig. 7 the 
inductance is represented by the spirals in the connecting 
wire between the Leyden jars and the spark-gap. In 
practice the inductance usually consists of a dozen or 
so turns of copper wire, about £ inch in diameter, wound 
spirally around a wooden frame. In Fig. 6 the induc¬ 
tance is shown placed around the spark-gap; this, how¬ 
ever, is simply a matter of design. 

Referring again to Fig. 7, one side of the inductance 
is permanently connected to the ground. There are 
two other wires flexibly connected to the inductance, 


The Apparatus Used 


21 


one of which is connected to the spark-gap; the other 
is the antenna. These wires are so arranged that they 



Fig. 8 . — High-power Outfit, with Rotating Spark-gap 
Mounted on Leyden - jar Battery Frame, and Hot¬ 
wire Current Meter Mounted on Inductance Frame. 
—Navy Yard , Washington , D. C. 


may be connected to any point on the spirally wound 
wire of the inductance. 












2 2 


Wifeless Telegraphy 


12. THE ANTENNA 

What is probably the most striking characteristic of 
a shore station is the very tall mast which towers above 
the operating building. This mast supports a wire, or 
group of wires, known as the antenna. 

The antenna possesses electrical capacity (also induc¬ 
tance), and, therefore, when connected with other ap¬ 
paratus, as in Fig. 7, it disturbs the earth’s magnetic 
field, as was fully described in Art. 5. 

The antenna is connected to the inductance through 
one of the flexible connections, as shown in Fig. 7. The 
length of the antenna varies according to conditions, 
the supporting mast in some cases being nearly 200 feet 
high, and in at least one case the height is 418 feet. 
The antenna is sometimes attached to captive baloons 
or to kites, and suspended in this manner for temporary 
service, as in military operations. On boats the antenna 
is attached to the masts. 

13 . TUNING THE TRANSMITTING APPARATUS 

As explained in Art. 5, it is necessary to have the oscil¬ 
lations of the Leyden jars in synchronism with the antenna 
circuit. The adjustment is made on the inductance coil 
as shown in Fig. 7. It can be readily seen that the Ley¬ 
den jars and antenna circuits can be adjusted independ¬ 
ently of one another, but always having more or less 


Fig. 9.—Mast for Supporting Antenna, Fessenden Trans-Atlantic Station, Brant Rock, Mass. 


The Apparatus Used 


2 3 










24 Wireless Telegraphy 

turns of the inductance coil common to both circuits. 
When the two circuits are adjusted to the same frequency, 
the discharge of the Leyden jars, through the few turns 
of wire in the inductance, will induce oscillations in the 



Fig. io.—Method of Suspending Antenna between Masts 

of Vessels. 


antenna, which in turn cause the disturbance in the mag¬ 
netic field of the earth. 

There are several means by which it may be deter¬ 
mined when the two circuits are in harmony with one 









The Apparatus Used 25 

another. One method is to insert a hot-wire current 
meter between the antenna and the inductance, which 
will indicate the strength of the oscillatory current set 
up in the same. By manipulating the flexible connec¬ 
tions, a maximum reading will be obtained, which will 
indicate that the two circuits are in synchronism. 

In the other method a device is used which accurately 
indicates the wave length. With this instrument the 
frequency of one circuit can be measured, and then the 
other circuit adjusted to give a corresponding wave 
length. 

Since the wave length is dependent on the frequency 
of oscillations, which in turn is dependent upon the 
capacity and inductance of the oscillatory circuits, it 
should be clear that the larger the antenna, the longer 
will be the wave length, and, necessarily, the greater 
the capacity of the Leyden jars. The power required 
is always in proportion to the wave length; that is, for 
the most efficient results. 

In practice it is customary to use a short wave length 
for low-power short-distance equipments, and a long 
wave length for high-power long-distance systems. This 
may be readily understood when we consider that more 
energy is required to make long, deep waves in water, 
than is required for the short and shallow waves. 


26 


Wireless Telegraphy 


14. THE RECEIVING APPARATUS 

While some wireless systems employ separate anten¬ 
nae for sending and receiving the messages, the same 
antenna is used for both purposes- in most cases, and we 
may, therefore, describe the receiving apparatus in the 
inverse order of the transmitting system. 

Art. 5 explains how the oscillations are set up in the 
receiving antenna and, also, how they must be adjusted 



Fig. 11.—Microphone with Telephone Receivers Connected. 


to the same frequency as that of the passing waves from 
the transmitting station. Referring to Fig. 3, C r repre¬ 
sents the antenna connected through the adjustable 
inductance I'. Adjustably connected with this induc¬ 
tance is also a small capacity, called a condenser , which 
with the inductance forms a closed oscillating circuit. 
The vibratory motion in the antenna is adjusted by mov¬ 
ing the connection y. The frequency of the closed cir¬ 
cuit is adjusted by changing the position of point v. In 





The Apparatus Used 


2 7 


practice the condenser is also adjustable so as to increase 
the range of wave length. 

When the two circuits are adjusted to harmonize with 
the received waves, an electrical pressure is created in 
the condenser, which pressure can be detected and made 
manifest by suitable apparatus. This part of the system 
is called a detector. 


15. DETECTORS 

The function of the detector is to respond to, and make 
manifest in some manner, the electric oscillations set up 



in the receiving circuits. There are many devices that 
will serve this purpose. They are used in connection 











28 


Wireless Telegraphy 



with a telephone receiver, the telephone being sensitive 
to very weak currents of electricity, which are made 
manifest by a “noise” in the telephone receiver. This 


Fig. 13.—Detector Mounted on Wave Meter. 

noise, or buzzing sound, corresponds to the sound of the 
spark at the sending station; thus an operator may often 
recognize a distant station by the sound of the “spark” 
in his telephone receiver. 

One type of detector is known as the Microphone. 






The Apparatus Used 


29 


This, in one of its simplest forms, comprises two blocks 
of carbon with sharp edges, across which rests a steel 
needle. This type is illustrated in Fig. 11, and its simplest 
connections are shown in Fig. 12. The steel needle rest¬ 
ing across the carbon blocks forms an imperfect contact. 
When the high-frequency oscillations pass through the 
carbons and the needle, the contact is greatly improved, 


ANTENNA 


RLAT/NOM W/RE 


CON 


BATTERY <m 


< 2 > 


telephone 

GROUND T 

Fig. 14.—Connections of Electrolytic Detector. 


with the result that the local battery current will be 
strengthened in nearly direct ratio to the improved 
contact. This change of current causes a sound in the 
telephone receiver. 

Another type used in connection with the telephone 
receiver is called the Electrolytic Detector. This consists 
of a small cup containing nitric or other acid, into which 
the end of a very fine platinum wire is slightly immersed. 
Fig. 14 shows the principle. It will be observed that the 









3 ° 


Wireless Telegraphy 


connections are very similar, although the principle is 
quite different from that of the microphone. In the elec¬ 
trolytic detector, a film of gas forms between the end 
of the platinum wire and the acid, which acid is a con¬ 
ductor of electricity. This film of gas insulates the plati- 



Fig. 15.—Magnetic Detector. 


num wire from the acid. Hence there will be practically 
no current flowing through the telephone receiver. In 
the presence of the high-frequency oscillations, however, 
the resistance of the gas film is reduced, which allows an 
increased battery current to flow through the telephone 
receiver. The sudden rush of the battery current through 




The Apparatus Used 31 

the telephone receiver produces sound, as already de¬ 
scribed. 

The platinum wire employed in the electrolytic detector 



Fig. 16.—Silicon Detector. 


is so fine, and the method of its manufacture so unique, 
that we here describe it. 

A heavy platinum wire approximately one one-hun¬ 
dredth of an inch in diameter is coated with a suitable 
thickness of silver. The combined silver and platinum 
wire is then drawn down to the . desired diameter. The 
close-fitting silver jacket prevents the rupturing of the 





3 2 


Wireless Telegraphy 


platinum wire within during the drawing process. The 
silver is then removed by immersing in nitric acid, which 
leaves the platinum only. Platinum wires have thus 
been drawn down to .00006 of an inch. 

Another type, known as the Magnetic Detector , is based 
upon the phenomena that certain magnetic characteris- 


A/vrc/v/v/t 


BPASS PO//VT 
S / L/C OH BLOCH t "7" 1 


•=T GHOo/yo 

Fig. 17.—Connections of Silicon Detector. 

tics in iron undergo a change under the influence of the 
high-frequency oscillations. This detector is illustrated 
in Fig. 15. It requires no local battery, but must be 
rotated by means of clockwork or a small electric motor. 
The regular telephone receiver is also used with this 
detector. 

What is probably the simplest type of all is known 
as the Silicon Detector* This consists of a piece of silicon 



T £ L £ PH 6 N £ 


* Patented by Prof. G. W. Pickard. 















The Apparatus Used 


33 


with a brass point resting against it. In the presence 
of the high-frequency oscillations, the particles at the 
point of contact are heated, which causes a sound in the 
telephone receiver. The silicon detector is illustrated 
in Fig. 16, and Fig. 17 shows its connections. 


CHAPTER IV 
METHOD OF OPERATING 

l6. SWITCHING DEVICE 

While, as before stated, in some cases separate antennae 
are used for sending and receiving, it is common practice 
to use the same antenna for both. This is accomplished 
by means of a switching device so arranged that when 
the transmitter is connected in, the receiver is cut out. 
This is absolutely necessary, as otherwise the delicate 
receiving apparatus would be destroyed should the high- 
power currents of the transmitter pass through it. 

17. SENDING THE MESSAGE 

In Fig. 18 are shown several types of keys used in wire¬ 
less telegraphy. The operator sends the message by 
pressing the key lever downward, or allowing it to remain 
up for certain periods of time. Pressing the key lever 
downward for a brief interval represents a dot, and a 
longer period of depression, a dash. The proper arrange¬ 
ment of dots and dashes forms letters, and combinations 

of letters of course form words, etc., the letters being 

34 


Method of Operating 


35 


spaced by holding the key lever up for a given period of 
time, and the words being spaced by still longer periods. 

The proper arrangement of the dots, dashes, and 
spaces constitutes a code. The Morse code is extensively 
used in America, while a modification of it, called the 
Continental code, is employed in England and on the 



' A|'^ 






v , 








Fig. 18.—Types of Keys. 

continent of Europe. These are shown in Fig, 19. When 
the key lever is depressed, two insulated pieces of plati¬ 
num, called contacts, touch one another, closing the low- 
pressure circuit of the induction coil or transformer. 

When an operator desires to communicate with another 
station, he first “listens in” by connecting his receiving 
system with the antenna and the ground, and placing 









36 


Wireless Telegraphy 


the telephone receiver to his ears. He then adjusts his 
receiving circuits for various wave lengths and, if he 
hears no signals, he assumes that no one else is sending 
within his radius. He therefore “throws in” the trans¬ 
mitting apparatus, which action automatically discon¬ 
nects the receiving side. He then sends the letters 
which constitute the “call” of the station desired, sign¬ 
ing the letters designating his own station, after sending 
the call several times. He then listens in again, and if 
the operator at the desired station has heard his call, 
the latter answers, and regular telegraphic communica¬ 
tion ensues. 

Some wireless systems are so arranged that no switch¬ 
ing is necessary. The operators can “break” one another, 
by keeping the telephone receivers over their ears all 
the time. If the receiving operator should wish to cor¬ 
rect the sender, he does so by pressing his key; this is 
heard by the sending operator when his key is in normal 
position. 

Tuning not only increases the radius of operation, but 
maintains secrecy as well. By means of careful tuning, 
two distant stations may be sending simultaneously, 
and if they employ different wave lengths, the operator 
at the receiving station may, by adjusting his apparatus 
to the wave length of the station with which he desires 
to communicate, “tune out” the other message, receiv¬ 
ing only the one desired. 

However, if the stations above referred to be quite 


Method of Operating 


37 


LETTERS MORSE 

c — - 

E 

H - 


CONTI N ENTAL 


J 

K 

L 

M 

N 

o 

p 

Q 

R 

5 
T 
U 

V 

w 

X 

Y 

z 

6 


1 

2 

3 

4 

5 

6 

7 

8 
9 
0 

. Period 



N U M ERALS 


PUNCTUATIONS. ETC. 


( Comma — - — - — - ~ — 

7 Interrogation -— -- 

1 Exclamation ~ 

Fig. 19.—Wireless Telegraph Codes. 














3 8 


JVireless Telegraphy 


near one another, as in the case of two or more boats 
passing a shore station, the operator may not be able 
to tune out the undesired party, owing to their proximity, 
and the apparatus is then said to be operated by “forced 
oscillations.” Nevertheless an operator may receive the 
desired message by concentrating his mind upon the 
sound of the “spark” of the desired transmitting station, 
but this may only be done when the sounds of the “sparks” 
are dissimilar, or one is louder than another, owing to 
different strengths, or to varying distances. 


CHAPTER V 
HISTORICAL 

l8. EARLY ATTEMPTS 

Attempts to establish communication electrically 
through a natural medium (that is, without the use of 
a wire connecting the stations) were made in the begin¬ 
ning of the nineteenth century. 

Some inventors worked on the principle of the con¬ 
ducting power of the earth, and others upon the principle 
of electrostatic or electromagnetic induction. Of these 
latter types the Phelps and Edison systems were devised 
with a view of telegraphing to moving trains, while the 
Preece system was employed to communicate between 
an island and the mainland, utilizing both of the above 
principles. 

The vertical aerial wire was first employed by Dolbear 
in 1886 in connection with a peculiar conduction system. 
Mr. Edison in 1891 proposed to support vertical wires 
by captive baloons, in connection with an induction 
telegraph. 

Thus it is seen that the antenna (or vertical wire, as 

39 


40 


Wireless Telegraphy 



it was then called) was proposed before the principle of 
the real wireless telegraph was discovered, as the follow¬ 
ing retrospect will show. 


Fig. 20. —Wireless Operator’s Desk, Signal Corps U. S. A. 
19. DEVELOPMENT OF WIRELESS 

Although Clerk-Maxwell proved the electromagnetic 
theory of light, mathematically, in 1864, it was not ex- 







Historical 


41 


perimentally demonstrated that electric waves exist in 
free ether until 1888, when this great discovery was made 
by Professor Hertz. 

The apparatus used by Professor Hertz, to generate 
the high-frequency oscillations, was, naturally, a simplified 
form of the generating apparatus of to-day, but without 
any antenna or ground connections. For a detector he 
employed a loop of wire with the ends nearly touching 
one another. When the generator, or “oscillator,” was 
set in operation, and the loop of wire was held near it, 
minute electric sparks were seen to pass between the ends 
of the wire constituting the loop, and the existence of 
the free ether waves was thus proved. 

So great a discovery naturally set scientists, the world 
over, to experimenting, and in 1890 Dr. Branly discov¬ 
ered that loose metal filings, which normally have a high 
resistance, become fairly good conductors of electricity 
in the presence of electric oscillations. Dr. Branly 
demonstrated this by placing the filings between metal 
plugs in a glass tube, the device (which he called a Radio- 
Conductor) being connected in circuit with a battery 
and electric indicator. Professor Lodge called the Branly 
device a Coherer, and as it was found to be more sensi¬ 
tive than the Hertz detector, Professor Lodge combined 
the Hertz oscillator with the coherer in 1894, this form¬ 
ing the first complete wireless set. 

In 1895 Count Popoff attached a vertical wire to one 
side of the coherer of the Lodge receiver, and connected 


42 


Wireless Telegraphy 



Fig. 21.—Interior of Experimental Wireless Station. 





































Historical 


43 


the other side to the ground. This device was used in 
meteorological work to detect the approach of thunder¬ 
storms. He was, therefore, the first to use an antenna 
in connection with the real wireless telegraph. 

Having thus increased the working range of the re¬ 
ceiver, it only remained to connect an antenna to the 
transmitter; this was done by Marconi in 1896. Since 
that time improvements have been made in the trans¬ 
mitting and receiving devices, and the distances of com¬ 
munication have been increased from a few hundred feet 
to several thousand miles. 

The development of very sensitive detectors has had 
much to do with the progress of wireless telegraphy. The 
Fessenden electrolytic detector is, probably, the most 
efficient type. 

Nikola Tesla has rendered important service in the 
development of high-frequency apparatus, and is now 
experimenting with a system to transmit power without 
the use of wires. 


CHAPTER VI 


THE USES OF WIRELESS TELEGRAPHY 

20. PUBLIC SERVICE 

That branch of the wireless service which probably 
appeals most to the reader is the public service. A com¬ 
paratively few years ago, when the tourist bade his friends 
adieu as the steamer started on its ocean voyage, it was 
with the knowledge that they and the rest of the world 
would be as dead to him until he should arrive at his 
destination, at some distant port across the ocean, or, 
perhaps, far down the coast. Important events might 
develop in his business, or other personal matters come 
up, which only he could control; yet he would remain 
in absolute ignorance of the facts until the steamer arrived 
in port, when it might be too late for him to do anything 
to advantage in the matter. 

Wireless telegraphy has changed all this, however. 
The tourist crossing the ocean, or the business man travel¬ 
ling along the coast, goes with a feeling of perfect security. 
He goes with the knowledge that he may keep in constant 
touch with his family and his business, and may even 


The Uses of Wireless Telegraphy 45 

send social messages just for the novelty of it. If he is 
delayed by fog or snow-storm on a short trip, he sends a 
wireless,” stating the facts, and making a new appoint¬ 
ment, and the probable time of his arrival. 

But the use of wireless telegraphy, which should appeal 



Fig. 22.—Portable Receiving Outfits. 

the strongest to the travelling public, is its inestimable 
value in case of accident. 

21. VALUE TO SHIPOWNERS 

What mostly concerns owners of vessels is the fact 
that their steamers may keep in constant communica¬ 
tion with the office of the steamship company, and in 
case of accident assistance may be secured very quickly. 








46 


Wireless Telegraphy 


by appealing to other vessels which may be within use¬ 
ful distance, or through shore stations. 

When the operator on a coastwise steamer is reporting 
to the shore station at regular intervals, it gives assurance 
that if anything should happen to the steamer, aid would 
be quickly forthcoming, and the lives of the passengers 
and crew would be saved, as would also the hundreds of 
thousands of dollars represented in the steamer and valu¬ 
able cargo. 

This gives the passengers an assurance of safety, and 
the owners and Marine Insurance Companies a knowledge 
of increased protection; hence the owners should have 
less insurance to pay. 

When equipped with the wireless telegraph, a tug may 
take in tow, say, several barges laden with coal, from a 
southern port, and proceed northward along the coast, 
the captain having not the slightest idea where the coal 
will be sold. The agents are busy, however, and soon 
the captain receives an order by wireless where to drop 
a portion of his tow. After making this delivery, he 
proceeds on his way, and receives his wireless orders from 
time to time, until all his coal is disposed of. Had it not 
been for the wireless, he could not have proceeded until 
all, or at least a part, of the coal was sold; thus much 
time and money may be saved. 

Again, a steamer might proceed from a southern to a 
northern port in winter, and after the vessel was well up 
the coast, news might be received at the steamship office 


The Uses of Wireless Telegraphy 47 

fhat the harbor of destination was ice-bound. A short 
message by wireless would halt the steamer, thereby sav¬ 
ing much coal and other expense. 

22. TELEGRAPHING OVER LAND 

While greater distances may be covered by wireless 
telegraph over water, as was explained in Art. 5, it is also 



Fig. 23.—Portable Signal Corps U. S. A. Outfit “On the 

March.” 

used to a considerable extent 111 telegraphing over land. 
While as yet it has not entered into very active competi¬ 
tion with the regular wire service, it fills a great demand 
in communicating over wild countries, where the installa¬ 
tion and maintenance of a regular telegraph or telephone 
line would be impracticable. It is also much cheaper 








48 


Wireless Telegraphy 



Fig. 24 . —Portable Signal Corps U. S. A. Outfit “Ready for 

Business.” 



















The Uses of Wireless Telegraphy 49 

than the wire equipments, where the volume of business 
is not too great, and the distance warrants its use. 

Excellent results are reported from Alaska, where a wire 
equipment would be well-nigh impossible, owing to the 
heavy sleet and snow-storms, and to the further fact that 



the natives steal the wires. It is but natural that the 
wireless should be installed in districts where there has 
previously been no telegraph system whatever, and for 
this reason its use is common in sections like Central and 
South America. 

No force of linemen is required in connection with a 
wireless equipment, and so long as the station itself re¬ 
mains in working order, floods, snow-storms, tornadoes, 









5 ° 


Wireless Telegraphy 


and even earthquakes may occur without interfering with 
the wireless service, while any of the above disturbances 
usually suspend the wire business for days at a time, and 
communication is restored only after a considerable out¬ 
lay of money. 

In military operations portable outfits are used which 
may be set up, and messages transmitted and received 
upon a few minutes’ notice, while on the march or on the 
battle-field. Before the advent of wireless telegraphy, 
it was necessary to string wires over long distances and at 
great risk, and even then the enemy might at any moment 
cut the wires. 

Now that wireless has entered the field of commercial 
competition with the trans-Atlantic cables, its progress 
will be watched with the greatest interest. 


CHAPTER VII 


POSSIBILITIES AND ABUSES* OF WIRELESS 

TELEGRAPHY 

23. COMMERCIAL CONDITIONS 

To state that the wireless telegraph of to-day can pro¬ 
duce no better results than is being accomplished practi¬ 
cally, is erroneous in every sense of the word. Experi¬ 
mentally, wireless telegraphy is far in advance of the 
practical work. 

The faith of investors in wireless has been greatly 
shaken by their bitter experience with worthless wire¬ 
less stock, which they were induced to purchase through 
the gross misstatements of certain stock companies, and 
their continued efforts to unload this stock upon an 
innocent public. 

This has, naturally, brought about a period of inactivity 
as regards the extension of wireless telegraphy, for loss 
of confidence will cause the suspension of even the oldest 
and most firmly established business of any character. 


*See article by Frank Fayant in Success Magazine, June, 1907. 

5i 



5 2 


Wireless Telegraphy 


Financiers who ordinarily would be eager to grasp an 
opportunity of this kind now have no faith in the com¬ 
mercial prospects of wireless, as certain stock companies 
have not used the proceeds from the sale of stock in the 
development of their business. 

The officers and directors of telegraph and cable com¬ 
panies have also done a great deal to bring about the 
present conditions, by making statements which they 
knew to be wrong; but no doubt they felt they were 
justified in thus protecting their own interests. This 
is decidedly a very poor policy on their part, as they 
could greatly increase the value and earning power of 
their stock by utilizing wireless telegraphy in connection 
with their present service. However, their continued 
antagonism is only tending to force the wireless companies 
to take the initiative in establishing a service that will 
prove a powerful and successful competitor. The tele¬ 
graph and cable companies should bear in mind the op¬ 
position with which the efforts of Morse and Field were 
met in the early days of the arts of land-wire and cable 
telegraphy. 


24. THE PRESENT STATE OF THE ART 

Wireless telegraph to-day is in practical use over both 
sea and land. The ocean liners, as well as the coastwise 
vessels, keep in constant communication with land sta¬ 
tions, and thus render valuable service both to ship- 


Possibilities and Abuses of Wireless Telegraphy 53 

owners and the public. It is in use over land, contrary 
to statements of those who are foolishly trying to belittle 
the art, and as an example we will site the government 
stations at Washington, D. C., and Brooklyn Navy Yards, 
which stations are in constant communication both day 
and night, and can work with each other regardless of 
the interference of surrounding stations. This is by no 
means the limit of what can be done over land. 

Regardless of any statement to the contrary, wireless 
telegraphy is not limited to one line of communication 
between two points. It may be duplexed; that is, two 
or more messages may be sent and received simultane¬ 
ously. It can successfully compete with cables on all 
points. 

It is true that some of the stock companies have 
established communication over great distances of water, 
but results obtained with such installations should not 
be accepted as conclusive proof of what can be done, 
as these stations were installed more with an object ot 
bolstering up their stock, than any intention of estab¬ 
lishing a sound commercial business. 

The high-power stations of these companies are equipped 
with crude apparatus, that is more crudely installed, and 
depend more on the high power of their stations, than 
on perfected apparatus, to establish communication. 
Stations of one of the stock companies are equipped 
with 500-horsepower apparatus, which is used to com¬ 
municate over a distance of less than 2000 miles, while 


54 


Wireless Telegraphy 


one of our well-known inventors, representing a close 
corporation, has communicated over a distance of 3300 
miles with less than 40 horsepower. 

The Marine Insurance Companies are also doing their 
share towards belittling the value of wireless telegraphy, 
for although it can be proved that it has saved them thou¬ 
sands and thousands of dollars, they refuse to acknowl¬ 
edge it to be a safeguard to vessels, and will not lower 
the insurance rates to vessels equipped with wireless ap¬ 
paratus. 

To cite a case: On a recent trip the steamer City oj 
Puehla encountered a vessel that met with a mishap and 
was floundering about in the sea in a helpless condition. 
A wireless message was at once despatched to the nearest 
life-saving station, and in due time assistance arrived. 
The position of the floundered vessel was such that a ves¬ 
sel of heavy draught, such as the City oj Puebla , could be 
of no assistance. In answer to the despatch a light ves¬ 
sel was sent out and the vessel and crew were saved from 
destruction. 

Some of the coastwise vessels on the Pacific coast have 
repeatedly communicated with the government stations 
over distances ranging from 1600 to 2200 miles, with 
only a 4-horsepower outfit. This shows very clearly 
the difference in work, and results accomplished, between 
the stock companies and the close corporations. 


Possibilities and Abuses of Wireless Telegraphy 


25. INTERFERENCE AND GOVERNMENT REGULATION 

There has been much discussion regarding the regula¬ 
tions of wireless by governments, owing to the value 
of the art in time of war. For this reason certain gov¬ 
ernments have proposed to control and regulate the 
transmission of wireless messages at all times, which 
action would necessitate a license on the part of an oper¬ 
ating company for each station equipped and in opera¬ 
tion. Moreover, the government would have the right 
to grant or refuse such license as it saw fit. 

This agitation has been caused by legitimate wireless 
companies transmitting messages at a time when it would 
be convenient for the government stations to transmit 
messages, but owing to the fact that the wave lengths 
of the government and the independent stations were 
approximately the same, or owing to the proximity of the 
stations, it was impossible for both the government and 
independent stations to operate simultaneously. 

The question then arises whether, in time of peace, 
regular commerical wireless messages, which protect the 
lives of the passengers and crews of the steamers equipped 
with wireless, are not just as important as government 
wireless messages. If competing wireless companies have 
to wait for one another to transmit their messages, there 
appears to be no good reason why the government can¬ 
not do the same—in time of peace. 

It would be interesting to know whether the various 


5 6 


JVireless Telegraphy 


government officials are acting blindly, or are knowingly 
attempting to force legislation which will have the im¬ 
mediate effect of arresting the development of a valuable 
art and deprive the public of a service that would in time 
give them trans-oceanic telegraphy at one-tenth the rates 
now paid for cable service. 

This agitation, which would give the government full 
control of the wireless field, deals with existing condi¬ 
tions without considering the fact that wireless is still 
in its infancy, and is making enormous strides towards 
perfection each year. 

Where would our telegraph service be to-day had the 
government taken control of it in the forties, and said 
there could be only one wire between two places? It is 
true there is a great deal of interference between wire¬ 
less stations to-day, but is it to the best interests of all 
to have the government take control and say there shall 
be only one station in a locality, for the reason that 
another near-by station would cause interference? 

It would be far better to let the situation stand as it 
is, and give inventors an opportunity to overcome the 
present difficulties; and from our practical experience 
in this field, we believe that it will not be many months 
before this is accomplished. Under such an act we would 
be compelled to go to the government for a license when¬ 
ever we wished to build a station, in which case a permit 
would be granted if the station was to be in a locality 
distant from other stations. 


Possibilities and Abuses of Wireless Telegraphy 57 

For instance, assume that we should desire to establish 
an independent trans-Atlantic wireless service, and we 
should apply to the government for a permit, the locality 
being, say, somewhere on the New England coast. There 
are already numerous stations the entire length of the 
coast, and if we were fortunate enough to obtain a per¬ 
mit at all, it would be with restrictions to hours during 
which none of the other stations would care to operate. 
Moreover, is it to be supposed that the telegraph and 
cable companies would, should a law controlling wireless 
be enacted, remain passive and allow us to establish 
trans-Atlantic service, when a protest and a little in¬ 
fluence used in Washington would prevent it? 

The telegraph and cable companies have been very 
persistent in publicly ignoring wireless telegraphy as a 
competitor, but a recent circular issued to the managers 
of all its offices by the Western Union Telegraph Com¬ 
pany indicates the real attitude. In this circular it is 
ordered that all messages offered by the Marconi Com¬ 
pany for transmission to points on this side must be 
treated as local messages, be dated at Glace Bay, N. B., 
and be charged for at the local rate. “Code messages 
cannot be accepted in such messages, which must be fully 
addressed in accordance with the rules governing the 
transmission of domestic messages. If the Marconi wishes 
to give any indication of other origin, they must do so in 
the body of the message. The message must be checked 
at full commercial rate, whether addressed to a news- 


53 


Wireless Telegraphy 


paper, individual, or firm. Messages addressed to parties 
on the other side, routed via Marconi wireless or Glace 
Bay, cannot be accepted. We will, however, of course 
accept messages addressed to the Marconi Company, or 
any one else at Glace Bay, but no other direction or 
indication can appear in the address. Such messages 
should be checked at full commercial rates, and the tolls 
to Glace Bay only collected. We cannot under any cir¬ 
cumstances accept the Marconi tolls or anything beyond 
Glace Bay on these messages, but must treat them solely 
and wholly as local messages between the point of origin 
and Glace Bay.” 

It is very easy to read between the lines and note that 
the telegraph companies are realizing their danger from 
competition; and with the government innocently acting 
in their interest, the public would be deprived of all 
the benefits of legitimate competition. 

As for the development of wireless telegraphy, we have 
only to compare the present conditions in Great Britain 
and this country. When the Marconi Company was 
first formed it obtained a license or contract from the 
English government; as a result it is the only company 
to-day in England, and the English battle-ships have 
only such apparatus as the Marconi Company can give 
them. On the other hand, in the United States there 
are now seven or eight companies in vigorous com¬ 
petition, which has resulted in improvement of appara¬ 
tus and increase of efficiency to such an extent that our 


Possibilities and Abuses of Wireless Telegraphy 59 

navy to-day stands first in wireless and holds the record 
for long-distance communication. Our merchant marine 
is also getting the advantage of competition and receiv¬ 
ing wireless service at reasonable rates, while the Eng¬ 
lish merchant marine is compelled to use the Marconi 
system or none, and at whatever price demanded. 

As to the grievance of the government with respect 
to interference, we may cite a case that happened on the 
Sound last fall. A government message was being sent 
from Washington to Newport via Fire Island (all land 
stations); complaint was made because Sound boats 
interfered with the transmission, and it was asked that 
boat work should cease when government plants were 
sending. In time of peace, and when both the Western 
Union and Postal Telegraph Companies are rendering 
efficient service between Washington and Newport, is 
it just to make such a demand and use wireless to the 
detriment of the service of boats which are dependent 
wholly upon the wireless? 

* Any regulation of wireless telegraphy should be based 
on a full recognition of the fact that the art is now in its 
infancy, and that its proper development demands free¬ 
dom from every unnecessary restraint. Assuming that 
the government has some sort of prescriptive right to 
an art with which a long line of scientists and inventors 
has endowed the world, it does not follow that this right 


*From editorial in Electrical World, March 21 1908. 




6o 


Wir el ess Telegraphy 


cannot be exercised with due regard to the use of the 
same art for non-governmental purposes. If in time of 
peace occasions arise of sufficient importance to call for 
a temporary preemption of the ether by the government, 
any inconvenience thereby occasioned to commercial and 
private interests can be borne with some equanimity. 
But there should be some assurance that such interrup¬ 
tions are incident to matters of real importance—that 
all private interests are not sacrificed to routine com¬ 
munications that might just as well be transmitted by 
wire, or by trivial communications between officials. By 
defining in some manner the nature of government com¬ 
munications by wireless, and requiring a copy of every 
communication to be filed for critical examination as 
to its real importance, a gross abuse of the wireless privi¬ 
lege by an over-officious or inconsiderate official would 
be averted. 

In other words, in time of peace the preemption of the 
ether on the part of the government should only be for 
emergency purposes, and any official making an emer¬ 
gency call should be held strictly responsible for the 
rightful use of the privilege. In time of war, of course, 
wireless telegraphy would, in common with all the peace¬ 
ful arts of civilization, have to resign any claim to con¬ 
sideration; but as a recompense it should not be held 
in abeyance in time of peace in accordance with what 
appears to be a policy for the exaltation of the military 
over the other classes of American people—which classes 


Possibilities and Abuses of Wireless Telegraphy 61 

would be the ones to give their resources and offer up their 
lives in national defence, and not even balk if the nation 
should become committed through vainglorious bravado 
to a war of foreign aggression. None will, we believe, 
deny the need of some regulation of wireless telegraphy, 
but the character of such regulation should be the sub¬ 
ject of careful discussion in which the interests of the art 
and of the people as a whole should receive merited atten¬ 
tion. A means to this end would be the authorization 
by Congress of a commission to study the subject and 
report recommendations, the membership to be so chosen 
that the military and bureaucratic elements shall not 
dominate. We sincerely hope that no action will be 
taken by Congress until the subject of regulation has 
received in this country much broader and much wiser 
consideration than is evidenced in the bills thus far 
offered at Washington. 

26. THE OUTLOOK AND PROPHECY 

As before stated, it is the lack of capital behind private 
or legitimate enterprise that is holding back the develop¬ 
ment of wireless telegraphy; but even with this handi¬ 
cap, we firmly believe that, within five years from date, 
we will see it successfully competing with cables and 
trunk lines, and that our trans-Atlantic rates will be 
cut down to one-fifth of what they are to-day. 

From our experience and observations we are thoroughly 
convinced that within ten years the laying of trans-ocean 


62 


Wireless 1 elegraphy 


cables will be a thing of the past, for while the use of the 
present cables will undoubtedly be continued, the wire¬ 
less will be installed and maintained at a cost less than 
what would be the interest on the cost of a cable. 

The art of wireless telegraphy is still young. Scarcely 
a decade has passed since its practical value was first 
demonstrated. Important improvements are continually 



Fig. 26.—“Sea Otter.” The First Motor Yacht Equipped 

with Wireless Telegraphy. 

being made, and when more is known of the nature of the 
wonderful ether, more astounding discoveries in the field of 
wireless will undoubtedly be made, and this, together with 
the opening up of new channels for the application of 
the art, compels us to take a decidedly optimistic view. 













WIRELESS TELEPHONY 


Since wireless telegraphy has become so successful, 
it is but natural that wireless telephony should follow, 
just as the telephone followed the telegraph. In the 
ordinary wire telephone a transmitter is employed which 
varies the intensity of the electric current in the wire 
in direct ratio to the changes in the intensity of the sound 
waves set up by the human voice. All the undulations 
and tones of the voice are, therefore, transformed into 
complicated electric currents which, in passing through 
the telephone receiver, cause the diaphragm of the re¬ 
ceiver tq vibrate in unison with these complex currents, 
thereby reproducing articulate speech. 

The high-frequency oscillations employed in wireless 
telegraphy are so rapid that the human ear cannot detect 
their presence in a telephone receiver. Therefore it is 
plain that if means be employed to vary the intensity 
of these high-frequency oscillations by a telephone trans¬ 
mitter actuated by the human voice, the received waves 
may be made to so operate a telephone receiver connected 
to a regular wireless detector, that articulate speech may 

be reproduced in the telephone receiver. 

63 


64 


Wireless Telephony 


The first problem was to find means for generating 
a continuous flow of electromagnetic waves, without 
sufficient interruptions to cause a sound in the telephone 
receiver, excepting that caused by speech. It will be 
recalled that the sound heard in the telephone receiver 
employed in wireless telegraphy is due to the interrup¬ 
tion of the waves; hence the sound heard at the receiv¬ 
ing wireless telegraph station corresponds to the sound 
of the interrupted “spark'’ at the transmitting station. 

The principal method employed for producing a con¬ 
tinuous wave train is obtained by the use of an arc light. 
In this case, however, one carbon and a rod of cooper 
are employed instead of the usual two carbons. 

The electric arc is connected to a condenser which 
produces the high-frequency oscillations. By these means 
a nearly continuous train of waves is radiated from the 
antenna. 

A regular transmitter is connected in the antenna 
circuit as shown in Fig. 27, which when spoken into 
caries the strength of the high-frequency oscillatory cur¬ 
rent passing through it, thus varying or damping the 
electromagnetic waves. Almost any type of wireless 
telegraph receiver can be used as a wireless telephone 
receiver. 

Communication cannot be carried on over so great 
distances by the wireless telephone as by the wireless 
telegraph, owing to the fact that the best results in wire¬ 
less telegraphy are obtained by using sustained uniform 


Wireless Telephony 


65 


waves, whereas in wireless telephony the waves are 
damped, or, in other words, their form is changed by the 
effects of speech in the transmitter. Moreover, so great 


MTE/VNf\ 


TELEPHONE TRANSMITTER (O) 
C ONOENSER 



C-ROUA/0 

Fig. 2 -—Wireless Telephone Transmitter Connections. 


an amount of. energy cannot be handled with the wire¬ 
less telephone, as with the wireless telegraph. 

While wireless telegrams have been successfully trans¬ 
mitted and received over a distance exceeding 3000 

) 

> > 

) > 5 

> > 5 



















66 


Wireless Telephony 


miles, the wireless telephone has only been successfully 
used up to distances barely exceeding 20 miles, and those 
used in the U. S. Navy are only guaranteed to operate 
five miles. 

It is particularly adapted for service between the ves¬ 
sels constituting fleets, and for use on ferry-boats, tugs, 
etc., in harbors. 

However, the art is young, and no doubt the distance 
will be increased after we have obtained a better knowl¬ 
edge of the ether. 


THE FUTURE OF THE WIRELESS ART 


Mr. Nikola Tesla, in a recent interview by the 
authors, as to the future of the Wireless Art, volunteered 
the following statement which is herewith produced in his 
own words. 

“A mass in movement resists change of direction. So 
does the world oppose a new idea. It takes time to wake 
up the minds to its value and importance. Ignorance, 
prejudice and inertia of the old retard its early progress. 
It is discredited by insincere exponents and selfish ex¬ 
ploiters. It is attacked and condemned by its enemies. 
Eventually, though, all barriers are thrown down, and it 
spreads like fire. This will also prove true of the wire¬ 
less art. 

“The practical applications of this revolutionary princi¬ 
ple have only begun. So far they have been confined to 
the use of oscillations which are quickly damped out in 
their passage through the medium. Still, even this has 
commanded universal attention. What will be achieved 
by waves which do not diminish with distance, baffles 
comprehension. 

“ It is difficult for a layman to grasp how an electric cur- 

67 




68 


The Future of the Wireless Art 



. ;;; 


_JryA|Vr"- 




W" 1 -, 1 . wT '"V 


v* > -* 


THE TESLA WIRELESS PLANT ON LONG ISLAND 









The Future of the Wireless Art 69 

rent can be propagated to distances of thousands of miles 
without diminution of intensity. But it is simple after all. 
Distance is only a relative conception, a reflection in the 
mind of physical limitation. A view of electrical phe¬ 
nomena must be free of this delusive impression. How¬ 
ever surprising, it is a fact that a sphere of the size 
of a little marble offers a greater impediment to the pas¬ 
sage of a current than the whole earth. Every experi¬ 
ment, then, which can be performed with such a small 
sphere can likewise be carried out, and much more per¬ 
fectly, with the immense globe on which we live. This is 
not merely a theory, but a truth established in numerous 
and carefully conducted experiments. When the earth is 
struck mechanically, as is the case in some powerful ter¬ 
restrial upheaval, it vibrates like a bell, its period being 
measured in hours. When it is struck electrically, the 
charge oscillates, approximately, twelve times a second. 
By impressing upon it current waves of certain lengths, 
definitely related to its diameter, the globe is thrown into 
resonant vibration like a wire, stationary waves forming, 
the nodal and ventral regions of which can be located with 
mathematical precision. Owing to this fact and the 
spheroidal shape of the earth, numerous geodetical and 
other data, very accurate and of the greatest scientific 
and practical value, can be readily secured. Through 
the observation of these astonishing phenomena we shall 
soon be able to determine the exact diameter of the planet, 
its configuration and volume, the extent of its elevations 


7° 


The Future of the Wireless Art 


and depressions, and to measure, with great precision and 
with nothing more than an electrical device, all terres¬ 
trial distances. In the densest fog or darkness of night, 
without a compass or other instruments of orientation, or 
a timepiece, it will be possible to guide a vessel along the 
shortest or orthodromic path, to instantly read the lati¬ 
tude and longitude, the hour, the distance from any point, 
and the true speed and direction of movement. By 
proper use of such disturbances a wave may be made to 
travel over the earth’s surface with any velocity desired, 
and an electrical effect produced at any spot which can 
be selected at will and the geographical position of which 
can be closely ascertained from simple rules of trigo¬ 
nometry. 

“ This mode of conveying electrical energy to a distance 
is not ‘wireless’ in the popular sense, but a transmission 
through a conductor, and one which is incomparably 
more perfect than any artificial one. All impediments of 
conduction arise from confinement of the electric and 
magnetic fluxes to narrow channels. The globe is free of 
such cramping and hinderment. It is an ideal conductor 
because of its immensity, isolation in space, and geomet¬ 
rical form. Its singleness is only an apparent limitation, 
for by impressing upon it numerous non-interfering vibra¬ 
tions, the flow of energy may be directed through any 
number of paths which, though bodily connected, are 
yet perfectly distinct and separate like ever so many 
cables. Any apparatus, then, which can be operated 


The Future of the Wireless Art 


7 i 


through one or more wires, at distances obviously limited, 
can likewise be worked without artificial conductors, and 
with the same facility and precision, at distances without 
limit other than that imposed by the physical dimensions 
of the globe. 

It is intended to give practical demonstrations of these 
principles with the plant illustrated. As soon as completed, 
it will be possible for a business man in New York to dic¬ 
tate instructions, and have them instantly appear in type 
at his office in London or elsewhere. He will be able to call 
up, from his desk, and talk to any telephone subscriber on 
the globe, without any change whatever in the existing 
equipment. An inexpensive instrument, not bigger than 
a watch, will enable its bearer to hear anywhere, on sea or 
land, music or song, the speech of a political leader, the 
address of an eminent man of science, or the sermon of 
an eloquent clergyman, delivered in some other place, how¬ 
ever distant. In the same manner any picture, character, 
drawing, or print can be transferred from one to another 
place. Millions of such instruments can be operated from 
but one plant of this kind. More important than all of this, 
however, will be the transmission of power, without wires, 
which will be shown on a scale large enough to carry con¬ 
viction. These few indications will be sufficient to show that 
the wireless art offers greater possibilities than any inven¬ 
tion or discovery heretofore made, and if the conditions are 
favorable, we can expect with certitude that m the next 
few years wonders will be wrought by its application.’" 








V 


INDEX 


PAGE 

Adjustment of circuits. 22 

Alternating current. 15 

Antenna. 21, 26 

Arc light. 64 

Branly. 41 

Capacity. 11, 12 

Codes. 3 5-37 

Coherer. 41 

Condenser. 26 

Clerk-Maxwell. 40 

Current, Alternating. 14, 15 

Unidirectional. 14 

Low-frequency....,. 14, 20 

High-pressure. 14, 20 

Meter, hot-wire. 25 

Detectors. 27-32 

Discharge, Oscillatory. 17, 20 

High-frequency.*. 18 

Edison. 39 

Electrolytic detector. 29 

Electromagnetic waves. 2 

Ether. 1 


73 

























74 


Index 


PAGE 

Feddersen. 17 

Fessenden. 43 

Frequency of oscillations. 16 

Heat. 3 

Helmholtz. . 17 

Henry. 17 

Hertz. 41 

Inductance. 11 

Indtictance, the. 12, 20 

Induction coil. 14, 19 

Inertia, electrical. 20 

Interference. 55 

\ 

Kelvin. 17 

Keys. 34 

Leyden jar. 15 

Leyden-jar battery. 16, 19 

Light. 2 

Extreme red. 4 

Extreme violet. 4 

Ultra-violet. 4 

Light waves, speed of. 3 

vibration of. 4 

Lodge. 41 

Magnetic detector. 3 2 

Marconi. 43 

Mast for antenna. 22 

Meter, hot-wire current. 25 

Microphone. 2 8- 

Muffler . ! Q, 

Oscillations. I + 

Electric. . T 

































Index 


75 


PAGE 

Oscillations, Forced. 13, 38 

Frequency of. 16 

High-frequency. 14, 63 

High-pressure. 14 

Oscillator. 41 

Phelps. 39 

Platinum wire. 31 

Popoff. 41 

Portable outfits. 50 

Propagation of waves. 11, 12 

Public service. . 44 

Receiver, telephone. . . . 28 

Receiving apparatus. 8, 26 

Ruhmkorff coil. 15 

Silicon detector. 32 

Spark.. 16, 19 

Spark-gap. 18 

Switching device. 34 

Telephone receiver. 28 

Tesla. 43 

Special Article by. “ Future of the Wireless Art .. . 67-71 

Transformer-. 15 

Transmitting device. 8 

Tuning. 10 

The transmitting apparatus. 22 

Vibration in ether. 3, 15 

Wavelength. 5 > 2 5 

Wave motion. 2. 6 

W aves. 3 

Electromagnetic, light, heat, and wireless.. 3 































76 


Index 


PAGE 


Waves, complex. 4 

Ether. n 

Electric. 4 1 

Damped. 65 

Sustained. 64 

Wireless waves, over water and over land. 11 

frequency of... 15 









LIST OF WORKS 


ON 

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